The port forwarding from one ip to another ip in same network using iptables

Let’s say that we need to forward all connection to a port 143 IMAP to localhost to another server to a port 143 IMAP:

iptables -t nat -I PREROUTING -p tcp -d localhost --dport 143 -j DNAT --to-destination anotherserver:143
iptables -t nat -A POSTROUTING -p tcp --dport 143 -d anotherserver -j SNAT --to localhost

172.16.60.5 – localhost
172.16.10.77 – another server

# Forward port 143 IMAP to 172.16.10.77
iptables -t nat -I PREROUTING -p tcp -d 172.16.60.5 --dport 143 -j DNAT --to-destination 172.16.10.77:143
iptables -t nat -A POSTROUTING -p tcp --dport 143 -d 172.16.10.77 -j SNAT --to 172.16.60.5

# Log connection to port 143 to /var/log/firewall
iptables -t nat -I PREROUTING -p tcp --dport 143 -j LOG --log-prefix "IMAP PREROUTING: "
iptables -t nat -I POSTROUTING -p tcp --dport 143 -j LOG --log-prefix "IMAP POSTROUTING: "